Research Reports

Description:
The cathodic protection system on the I-405/SR-522 interchange near Woodinville, Washington was evaluated for proper operation. Three of the five zones on the bridge appeared to be cathodically protected. The current was increased in one of the unprotected zones to provide protection. The remaining zone could not be fixed due to the nonfunctional nature of thermistors, reference electrode and structure cables. A recommendation was made to deactivate the entire system for a period of two weeks to allow for depolarization. Following depolarization, native state potential valves should be measured to establish a basis of comparison before activating the system. Monitoring on a three month interval for one year should be done to ensure that all problems have been solved.